Method of manufacturing an archery broadhead with sintered components

ABSTRACT

The present invention relates generally to a method of manufacturing broadhead components utilizing a powder injection molding (PIM) process that reduces the number of operations, thus simplifying the manufacturing process required to produce a finished product while maintaining the precision essential to the function of this commodity. The method of manufacturing includes powder injection molding one or more than one components for a broadhead, sintering the component(s) at an elevated temperature to form component(s) and assembling the component(s) to form a broadhead.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of prior application Ser. No.09/910,385 entitled “Broadhead and Method of Manufacture” filed on Jul.20, 2001 now U.S. Pat. No. 6,595,881, which is a continuation in part ofprior application Ser. No. 09/546,146 entitled “Broadhead and Method ofManufacture” filed on Apr. 10, 2000 now U.S. Pat. No. 6,290,903 andwhich also claims priority under 35 U.S.C. §119(e) to U.S. ProvisionalPatent Application No. 60/219,474 filed on Jul. 20, 2000 and entitledExpanding Archery Broadhead, the specification and drawings of which arehereby expressly incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to an archery arrow and morespecifically to the design and method of manufacture of the broadheadfor an archery arrow.

The components of a typical archery broadhead include a ferrule or bodyhaving one or more blades extending therefrom. Additionally, the tip ofthe broadhead may be a separate component secured to the front of theferrule. Two types of archery broadheads are generally known in theindustry as fixed or replaceable blade broadheads and moveable ormechanical blade broadheads. The moveable blade broadheads, by design,are in a closed position in flight and open upon impact with the target.

Conventionally, the components of archery broadheads are manufacturedusing a variety of processes. The ferrule is conventionally turned orstamped with a male thread at the end where it attaches to an arrowshaft. Where the tip is not formed is as an integral of the ferrule, aninternal or female thread is formed on the front of the ferrule forreceiving and securing the broadhead tip. Additional machiningoperations are necessary to provide the slots or other openings in theferrule essential to the attachment of the blades. The blades aregenerally stamped steel with a uniform cross-section that requiressubsequent grinding and honing operations to provide the sharpenededges. Thus, removable blades adds add to the complexity of manufacturermanufacturing, as does the use of irregular skin surface treatments onthe ferrule. Tapered blades instead of stamped blades add strength andresistance to bending.

Broadhead components manufactured using conventional processes require avariety of costly equipment to achieve and maintain the precisionessential to proper functioning of this commodity. Accordingly, there isa need to provide an efficient method of manufacturing from of many ofthe broadhead components to reduce the cost, add design flexibility andstill maintain the precision required.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method ofmanufacturing broadhead components utilizing a process that reduces thenumber of operations, and thus simplifies the process, required toproduce a finished product while maintaining the precision essential tothe function of this commodity.

It is an additional object of the present invention to provide differentmaterials as dictated by the particular application, in the manufactureof broadhead components utilizing the aforementioned process.

It is another object of the present invention to provide a monolithicferrule, manufactured utilizing a powder injection molding (PIM) processincorporating integral design features necessary for the proper assemblyand functioning of the broadhead.

It is a further object of the present invention to provide broadheadblades, manufactured by the PIM process, with tapered or otherwisevarying cross sections so as to enhance the strength in and aerodynamicqualities of the broadhead.

It is yet another object of the present invention to provide blades,manufactured by the PIM process, having scalloped, serrated or otherwisevarying cutting edge treatments so as to enhance the cutting andpenetration abilities of the broadhead.

It is an additional object of the present invention to provide abroadhead point, manufactured by the PIM process which may be usedinterchangeably with a variety of ferrules.

It is still another object of the present invention to provide a ferruleand broadhead point, either separately or integral with the ferrule,manufactured by the PIM process having a surface texture so as toenhance the aerodynamic and penetration qualities of the broadhead.

In accordance with a first preferred embodiment of the presentinvention, an expanding-blade broadhead is provided including a ferrulehaving an integral boss formed thereon, a plurality of cutting bladessupported on the boss and pivotally coupled to the ferrule and a collarfor retaining the blades on the boss while permitting free rotationthereof. A threaded shank portion is formed on the end of the ferruleopposite the point for securing the broadhead to the arrow shaft in aconventional manner. The use of powdered metallurgy and subsequentsintering processes provides a preferred, but not essential method ofmanufacturing the ferrule and retaining collar.

In accordance with a second preferred embodiment of the presentinvention, a fixed blade broadhead is provided including a ferrulehaving a blade receiving slot formed therein, a broadhead tip threadedlysecured to the ferrule and a plurality of cutting blades disposed in theslots formed in the ferrule and releasably secured thereto by thebroadhead tip. A threaded shank portion is formed on the end of theferrule opposite the point for securing the broadhead to an arrow shaftin a conventional manner. The use of powdered metallurgy and subsequentsintering processes provides a preferred, but not essential method ofmanufacturing the ferrule, blades and broadhead tip.

These and other objects, features and advantages of the presentinvention will become apparent from the following description whenviewed in accordance with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an expanding-blade broadhead inaccordance with the present invention in which the blades are in aretracted position and with an arrow shaft illustrated in phantom lines;

FIG. 2 is a cross-section taken through lines II—II shown in FIG. 1;

FIG. 3 is a detailed perspective view illustrating the ferrule andretaining collar of the present invention;

FIG. 4 is a cross-sectional view of a portion of the ferrule and theretaining collar shown in FIG. 3;

FIG. 5 is an exploded side view illustrating the components of theexpanding-blade broadhead of the present invention;

FIG. 6 is a partial cross-section illustrating the pivotal connectionsbetween the ferrule and the cutting blade;

FIG. 7 is a side view of the expanding-blade broadhead shown in aretracted position;

FIG. 8 is a side view of the expanding-blade broadhead shown in thedeployed position;

FIG. 9 is an exploded side view of a fixed-blade broadhead in accordancewith the present invention with an arrow shaft illustrated in phantomlines;

FIG. 10 is a cross-sectional view taken through the ferrule portion ofthe broadhead illustrated in FIG. 9;

FIG. 11 is an alternate embodiment of a ferrule for the fixed-bladebroadhead having a surface texture treatment;

FIG. 12 is a cross-sectional view taken through the ferrule portion ofthe broadhead illustrated in FIG. 11;

FIG. 13 is a detailed cross-section view taken through the blade portionof the broadhead illustrated in FIG. 9 showing tapered bladepossibilities;

FIG. 14 is an alternate embodiment of the blade for the fixed bladebroadhead assembly illustrated in FIG. 9;

FIG. 15 is a schematic diagram generally illustrating the method ofmanufacturing components of the broadhead in accordance with the presentinvention using powdered metallurgy technology; and

FIG. 16 is a flow chart illustrating the method of manufacturing thecomponents of the broadhead in accordance with the present inventionusing powdered metallurgy technology.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference now to the FIGS. 1-8, a first preferred embodiment of thepresent invention is illustrated in the form of an expandable-bladebroadhead. Broadhead 10 includes ferrule 12, cutting blades 14 pivotallycoupled to ferrule 12 and collar 16 disposed over an end of ferrule 12for retaining cutting blades 14 thereon.

A substantially conical or trocar shaped tip 18 is formed at a forwardend of ferrule 12. The body 20 of ferrule 12 is generally conical ortrocar shaped having a triangular cross-section as best seen in FIG. 2.Each of the vertices 22 of body 20 has a slot 24 formed therein whichreceives cutting blade 14 when in the retracted position. Ferrule 12further has a base portion 26 having three lugs 28 extending radiallyfrom the ferrule. A boss 30 extends from the radial face 32 of lug 28.Shank 34 extends rearwardly from base portion 26 and has a male threadedportion 36 formed at the end thereof for operably coupling broadhead 12to arrow shaft 38.

Cutting blades 14 have a cutting edge 40 formed thereon. Aperture 42 isformed in a bottom portion of cutting blade 14 and is adapted toreceived receive boss 30 for pivotally coupling cutting blade 14 toferrule 12. Collar 16 is slidably received over shank 34 and has anannular skirt portion 44 with fingers 46 extending longitudinallyforward such that fingers 46 are positioned adjacent to lugs 28 formedon ferrule 12. A radial face 48 defined by fingers 46 is generallyparallel to but spaced apart from radial face 32 to further define slot24. As best seen in FIG. 6 a slight clearance is provided between theend of boss 30 and the radial face 48 of finger 46 such that collar 16may be readily positioned onto ferrule 12, while at the same timesufficiently retaining cutting blade 14 onto boss 30.

As best seen in FIG. 5, broadhead 10 is threadedly secured to arrowshaft 38 such that the forward face 50 of arrow shaft 38 pushesretaining collar 16 onto ferrule 12. As presently preferred, a compliantelement 52 is interdisposed between rearward face 54 formed on retainingcollar 16 and forward face 50 of arrow shaft 38 to prevent looseningtherebetween.

While various design features have been described above, one skilled inthe art will readily recognize that certain modifications, variationsand changes may be made without departing from the scope of theinvention. In this regard the overall shape and geometric configurationof the ferrule may be adapted to various shapes. In addition, theexpanding broadhead may incorporate more or less cutting blades as theparticular application requires. The retaining collar may be secured tothe ferrule by other suitable manners. The shaft of the ferrule may beformed of a separate piece from the body of the ferrule.

As previously indicated, some of the components of broadhead 10, and inparticular ferrule 12 and retaining collar 16 may be manufactured usinga powdered metallurgical manufacturing process resulting in monolithiccomponents. The powdered metallurgical process permits net shape or nearnet shape parts which have intricate design features. Furthermore, thepowdered metallurgical process provides greater control over the shapeand weight of the broadhead, and also improves the overall strength ofthe broadhead. The powdered metallurgical process also eliminates manyfabricating and machining steps associated with conventional broadheadmanufacturing.

With references now to FIGS. 9-14, a second preferred embodiment of thepresent invention is illustrated in the form of a fixed-blade broadhead.Broadhead 110 includes ferrule 112, and cutting blades 114 releasablysecured to ferrule 112. A conical or trocar shaped tip 118 is threadedlysecured at a forward end of ferrule 112 and functions to releasablysecure cutting blades 114 thereon. The body 120 of ferrule 112 isgenerally conically shaped having a triangular cross-section as bestseen in FIG. 10 and has a shank 134 extending rearwardly therefrom. Eachof the vertices 122 of body 120 has a T-shaped slot 124 formed thereinwhich releasably secures cutting blades 114 to ferrule 112.

Cutting blades 114 have a cutting edge 140 formed along the distal edgethereof. As best seen in FIG. 13, a bead 142 having a profile whichcompliments T-shaped slot 124 is formed along the proximal edge ofcutting blade 114. A generally triangular aperture 144 is formed in thebody of cutting blade 114 to reduce the overall weight of the broadheadand distribute the mass of the blade around its perimeter. As presentlypreferred, cutting blade 114 has a tapering cross-section from theproximal edge 146 to the distal cutting edge 140.

Slot 124 is configured to receive the proximal edge 146 of cutting blade114 including bead 142. Cutting blade 114 is slid axially into slots 124formed in ferrule 112. A threaded shank 148 is formed on the backsurface of broad tip point 118 and is received in a threaded aperture152 formed in ferrule 112. In this way, broadhead tip 118 retains andsecures cutting blades 114 with ferrule 112. While a T-shaped slotconfiguration and complimentary bead profile is presently preferred, oneskilled in the art will recognize that other slot configurations andbead profiles (such as L-shaped, circular, square, etc.) which cooperateto releasably secure blades 114 to ferrule 112 are contemplated by thepresent invention.

Broadhead 110 may be threadedly secured to arrow shaft 154 in the mannerheretofore described. A compliant element (not shown) may beinterdisposed between ferrule 112 and arrow shaft 154 to preventloosening therebetween. As presently preferred, blades 114 arereleasably secured to ferrule 112 by tip 118. However, one skilled inthe art will recognize that ferrule 112 could be configured such that aretaining element disposed over shank 134 or arrow shaft 154 functionsto releasably secure blades 114 to ferrule 112.

With reference now to FIG. 11, an alternate embodiment of the ferrule isillustrated. The body 120′ of ferrule 112′ is generally pyramidallyshaped having a triangular cross-section as best seen in FIG. 12. Eachof the vertices 122′ of body 120′ has a slot 124′ formed therein whichreceives cutting blades 114. The planar surfaces 121′ of body 120′ havea generally textured surface formed thereon for enhancing aerodynamicand penetration properties of the broadhead. In this regard, U.S. Pat.No. 5,871,410, the disclosure of which is expressly incorporated byreference herein, discloses a broadhead in which the ferrule has such atextured surface.

With reference now to FIG. 14, an alternate embodiment of the cuttingblades utilized in the present invention is illustrated. Specifically,cutting blade 114′ is generally triangularly configured having a cuttingedge 140′ formed on a distal edge thereof. In addition, a plurality ofscallops or serrations 141′ are formed in the cutting edge to furtherfacilitate cutting of the broadhead upon impact. Cutting blade 114′further includes a bead disposed along a proximal edge thereof forreleasably securing blade 114′ within ferrule 112 in a manner hereto fordescribed.

With reference now to FIGS. 15 and 16, a general description of apreferred method of manufacturing a broadhead in accordance with thepresent invention will now be described. A more detailed description isset forth in U.S. application Ser. No. 09/546,146 filed on Apr. 10, 2000and entitled “Broadhead and Method Of Manufacture”, the disclosure ofwhich is expressly incorporated by reference herein. The method ofmanufacture is schematically illustrated in flow chart 100.

The manufacturing process is initiated by blending metal powder andbinder to form a powdered metal composition as represented at block 102.When blending, the metal powder and binder are typically premixed in afirst blending step 102a and then fully mixed to a near homogenousmixture and pelletized in a second blending step 102b. In this regard, aparticular metal such as high carbon steel or titanium is mixed with asuitable binder such as a plastic or wax to form a powdered metalcomposition. Alternatively, plastic, ceramic or composite materialssuitable for powder injection molding (PIM) may be substituted for thepowdered metal composition described above. Next, as represented inblock 104, the powdered metal composition is injected into a broadheadmold 105 having the particular design configurations for fabricatingferrule 12 and collar 16 illustrated in FIGS. 1-8, or alternately forfabricating ferrule 112, cutting blade 114 and/or tip 118. One skilledin the art will recognized that the various PIM components of broadhead110 are formed separately. Through the use of pressure or other means,the powdered metal composition is compacted into a greenware broadbandcomponent having the precise geometric configuration of the finalproduct (although approximately 20% larger than the end design toaccount for shrinkage during subsequent processing) and moderatedensification (on the order of approximately 50 densification).

Next, as represented in block 106, the greenware broadhead component isprocessed to eliminate the binder from the metal without melting theconstituent metal, thereby forming a powdered metal broadhead component.As presently preferred, the greenware broadhead component is immersed ina solvent to separate a portion of the binder from the powdered metal asillustrated in block 106a. The greenware broadhead component is removedfrom the solvent and placed in a thermal debinding furnace representedat block 106b where any remaining binder is burned off. The thermaldebinding furnace may also be employed to perform a pre-sintering step.While the debinding steps is described as a combination of chemical andthermal processes, one skilled in the art will readily recognize thatany process or combination of processes could be employed to debind thegreenware broadhead. At this point, the powdered metal broadheadcomponent is still in a moderate densification state.

As represented at block 108, the powdered metal broadhead component isnext placed in a sintering furnace and sintered at an elevatedtemperature and pressure to achieve near full density thereof. Thesintering processing parameters are defined such that the broadheadreaches a density of at least 97%. During the sintering process, theoverall size of the broadhead shrinks approximately 20%. Once sinteringis complete, the broadhead component has a net shape and does notrequire further machining. In addition, the various features includingslots, bosses and threaded shanks are already formed in the ferrule.Lastly, as represented at block 110, cutting blades are secured to theferrule in a final assembly process of the broadhead.

As presently preferred, the broadhead components of the presentinvention are fabricated using a powdered metal technology. However, oneskilled in the art will readily recognize that other powdered materialssuch as ceramics or plastics may be suitable, and thus utilized herein.The determination of the exact materials are dictated by therequirements of a given application.

From the foregoing description, one skilled in the art will readilyrecognize that the present invention is directed to an archery broadheaddesign and a method of manufacturing same. While the present inventionhas been described with particular reference to preferred embodiments,one skilled in the art will recognize from the foregoing discussion andaccompanying drawings and claims, that changes, modifications andvariations can be made in the present invention without departing fromthe spirit and scope thereof as defined in the following claims.

1. A method of manufacturing an archery broadhead comprising: powderinjection molding at least one broadhead component selected from thegroup consisting of a ferrule and a blade , with a powdered metalcomposition, a ferrule including a body and defining a slot; sinteringsaid at least one broadhead component ferrule at an elevated temperatureto form a sintered broadhead component ferrule, the slot being formedand bounded substantially by metal; and connecting said a blade to saidferrule.
 2. The method of manufacturing an archery broadhead of claim 1wherein said blade is releasably secured to said ferrule with aretainer.
 3. The A method of manufacturing an archery broadhead of claim1 comprising: powder injection molding at least one broadhead componentselected from the group consisting of a ferrule and a blade; sinteringsaid at least one broadhead component at an elevated temperature to forma sintered broadhead component; and connecting said blade to saidferrule, wherein said blade is pivotally coupled to said ferrule with aretainer so that the blade is expandable from a retracted position to adeployed position.
 4. The method of manufacturing an archery broadheadof claim 1 further comprising: forming a greenware ferrule from apowdered composition; sintering said greenware ferrule at an elevatedtemperature to form a sintered ferrule; and connecting said blade tosaid sintered ferrule with said a retainer.
 5. The method ofmanufacturing an archery broadhead of claim 4 wherein forming agreenware ferrule comprises forming said ferrule having a shank portionextending from an end thereof.
 6. The method of manufacturing an archerybroadhead of claim 4 wherein forming a greenware ferrule comprisesforming said ferrule having a tip portion extending from an end thereof.7. The A method of manufacturing an archery broadhead of claim 4comprising: powder injection molding at least one broadhead componentselected from the group consisting of a ferrule and a blade; forming agreenware ferrule from a powdered composition; sintering said greenwareferrule at an elevated temperature to form a sintered ferrule; andconnecting said blade to said sintered ferrule, wherein forming agreenware ferrule comprises forming a ferrule having a boss formedthereon, said boss being received in an aperture formed in said blade topivotally couple said blade to said ferrule.
 8. The method ofmanufacturing an archery broadhead of claim 4 wherein forming agreenware ferrule comprises forming a ferrule having a slot formedtherein and said blade is received within said slot to releasably securesaid blade to said ferrule.
 9. The method of manufacturing an archerybroadhead of claim 1 further comprising: forming a greenware blade froma powdered composition; sintering said greenware blade at an elevatedtemperature to form a sintered blade; and connecting said sintered bladeto said ferrule with said a retainer.
 10. The method of manufacturing anarchery broadhead of claim 9 wherein said ferrule is provided with alongitudinal slot and said blade is received within said slot toreleasably secure said blade to said ferrule.
 11. The A method ofmanufacturing an archery broadhead of claim 10 comprising: powderinjection molding at least one broadhead component selected from thegroup consisting of a ferrule and a blade; forming a greenware bladefrom a powdered composition; sintering said greenware blade at anelevated temperature to form a sintered blade; and connecting saidsintered blade to said ferrule, wherein said ferrule is provided with alongitudinal slot and said blade is received within said slot toreleasably secure said blade to said ferrule, wherein forming agreenware blade comprises forming said greenware blade having a beadalong an edge thereof, said bead received within said slot when saidsintered blade is releasably secured to said ferrule.
 12. The method ofmanufacturing an archery broadhead of claim 8 further comprising:forming a plurality of greenware blade from said powdered composition;sintering said plurality of greenware blades at an elevated temperatureto form a plurality of sintered blades; and connecting said plurality ofsintered blades to said ferrule with said a retainer.